Note: All planetary positions in this article refer to the sidereal Zodiac which is currently 23 degrees 49 minutes and 30 sec behind Tropical Zodiac. Nakshatras are fixed stars or lunar mansions.
1) The Mythology
2) Understanding Rahu and Ketu in our natal charts
3) Vedic Hymn to Rahu
4) Rahu and the Nakshatras
6) Vedic Hymn to Ketu
7) Ketu and the Nakshatras
8) Kaal Sarp
9) Yog Transitions
Rahu and Ketu are names given to the two Nodes of the Moon. Rahu is the North Node while Ketu is the South Node. Rahu and Ketu are lunar points of the elliptical path. During eclipse, Moon, Sun, and Earth are positioned in one line. Rahu-Ketu signals exact point of agreement with three most important powers namely Sun, Earth and Moon. Thus, this planetary relationship plays an important role in enfolding of one’s consciousness.
Rahu and Ketu have roles as karmic indicators in one’s life. They have their powers in connection to causing eclipses. Eclipses occur in surrounding area of Rahu and Ketu during full moon and new moon. During new moon when it is +/- 18 degrees from Rahu Ketu, the solar eclipse takes place. During full moon +/- 11 degrees 15' from nodal position the lunar eclipse takes place. Symbolically eclipse of Sun [consciousness] and Moon [mind] are important. It plays a great role in darkening one’s perspective so that there is new light. Rahu and Ketu deal with concept of death, re-birth, transformation, and regeneration. During eclipses the light from the luminaries is darkened. The energies created are strongly supernatural and loaded with new information and occult power. The period after the eclipse is considered a rebirth of the Sun and the Moon. The role of Rahu- Ketu in this strong alignment of Sun, Moon and Earth allows them to be the ultimate controllers of destiny.
In the Vedic Astrology, the key feature is the most importance of Rahu- Ketu. They have been given the status of planets to stress their worth and importance placed on eclipses. They are known as Chayya Grahas [shadow planets]. Since they have no substance, they are physically non-existent. Their manipulation is full of strength and spiritual importance. Rahu and Ketu work as a unit, 180 degrees apart. They are always at two opposite points in the zodiac.
Their aim is to stir one’s life to outside hidden ability and wisdom. They keep to their shadowy nature and they work on a mental level. It is always difficult to determine their effect because they are mainly concerned with one’s sensitive makeup. They always affect one internally. Hence, one is not aware of what is precisely happening to us at the time.
In Vedic Astrology, the concept of soul's journey through different lifetimes is centred to it. The final goal of soul is to break this cycle of life and death. Like the beads on a necklace, various lifetimes are joined together to form a necklace. Separate lifetimes differ but they are interrelated by the invisible thread of Rahu and Ketu. The intension of soul in this life is to enact his given Karma. This includes destroying illusions of materialistic life and moving towards pursuit of self realisation. One should live on astral planes where pleasure or pain does not hurt. Also, the mind is quiet and at calm. In a particular lifetime, the soul’s journey is connected with exterior life. This is indicated by the position of Rahu and Ketu. Ketu deals with past Karma and Rahu with the future.
There are five impulses that keep us attached to materialistic purpose of life. These are Kaam [Desire, passions], Krodh [Anger], Madh [intoxicants- drugs, alcohol etc], Moh [Attachment], Lobh[Greed] and Matsaya[Jealousy]. One requires controlling one’s character rather than allowing oneself to be controlled by them. Both Rahu and Ketu can influence one’s mind that gets focused to these senses. However, they work slightly differently; Rahu works by over stressing while Ketu works by blocking.
One is tied down to the cycle of unhappiness and discontent because one cannot break away from one’s lower selves. Thus, one is born again and again going through pleasures and pains of worldly life. This cycle of life after and death continues till one understands that one is living in a fantasy. Unintentionally, one is afraid of giving up desires. This is because one thinks that one would suffer loss from it. After one begins to understand the attitude of letting go, one gets to enjoy what life has in store. One should enjoy life without any attachment. Best is when one grows spiritually. Rahu and Ketu deal with the inner fight. The moral and social choices one has to constantly make depend on the inner problems.
There are many myths and legends in connection with Rahu and Ketu. Most well-known legend of Rahu- Ketu is Naga Vasuki, ruler of Patala Loka [posterior regions of Earth]. According to Vedic literature, Nagas are not ordinary snakes; however, they are serpents with lots of hidden knowledge and wisdom. Gods and demons had a great war. Both of them were interested in controlling the universe. At the centre, there was the ocean that had to be churned to find all the hidden treasures. One was the Amrita, nectar of immortality. Vasuki helped the Gods to meet their undertaking. Vasuki became the rope tied around the spiritual mountain Mandara that acted as the rod. Both Vasuki and Mandara together were used by the Gods to churn the ocean.
When Amrita was found, the Gods wanted to keep it for themselves. The Gods decided that demons would use it for wrong purpose. Since Vasuki was a demon, his natural feeling was for personal adoration and worldly happiness. Vasuki was not interested in any good for the universe. Vasuki’s self sacrifice for others was considered Godly character. Vasuki was more intelligent than other demons. Since Vasuki did not want to be distracted by the Gods, he secretly drank nectar of immortality. The Sun and the Moon complained to Lord Vishnu, the creator of the Universe. Being angry, Lord Vishnu threw his Sudharshan Chakra at Vasuki who was cut into two. However, since Vasuki had already tasted Amrita he could not be killed but remained immortal. Vasuki remained in the skies as Rahu [the head] and Ketu [the lower half]. They constantly remind other planets [Gods] of life’s darker sides. One has to overcome the darker sides of life in order to get immortality.
Rahu and Ketu became enemies of Sun and Moon because they had informed Lord Vishnu. Rahu and Ketu symbolically swallow two luminaries during the eclipses. They have the capacity to darken the Sun and the Moon. Hence, they have high power to influence the Zodiac. Sun is at the centre and around it all other planets of solar system revolves. Moon controls life on earth. Both, Sun and Moon are hidden by Rahu and Ketu during eclipses. Rahu and Ketu represent cosmic law that everyone including the Sun and the Moon also obey.
This parable has to be understood as life. Gods without the help of Vasuki [Rahu Ketu] could not find the secret of immortality. Thus, humans cannot discover higher selves without understanding the lessons of Rahu and Ketu. They signify the darker side of one’s character that needs to be overcome. One’s inner emotions are like the ocean being churned. Hence, from this ocean emerge treasures and poisons or nasty things.
One has to recognise the difference between precious and unpleasant. Finally, one has to find Amrita, the secret of immortality that is true happiness. There is always a clash between material achievement and everlasting bliss. These are accomplished as follows: Rahu’s sphere of influence leads to material gain. However, this brings only momentary happiness or fantasy that is totally baseless. Opposite to being happy for getting materials, is liberation of soul that brings serenity. This is controlled by Ketu, the Moksha Karaka, important for spiritual realisation. The Gods needed the help of Vasuki in the Amrita Manthan. Similarly, we require the knowledge provided by wise nodes to give direction.
Understanding Rahu and Ketu in our Natal Charts:
We have to understand the influence of Rahu and Ketu in our chart. Hence, we have to must learn about their shadow nature. This is the most important factor while dealing with the influence of nodes. They are only points in the Zodiac. Therefore they are unable to enact their effect on their own. The nodes take on the characteristics of their saver as they have no substance themselves. It is very important to study the sign, position and placement of the depositor. Here it is important to understand that although the nodes are influenced by their saver. The depositor itself carries forward the influence of the nodes. The basic results of Rahu and Ketu are modified by their location in your chart. The signs/houses they are placed in. The features they receive and the characteristics they throw out when they are in combination with another planet. Note that in Vedic Astrology, the planet in the same house was considered in union. When the planet was near Rahu or Ketu, the influence was stronger. For example, if Rahu is in combination with Mars then it throws the features of Mars along with that of its depositor.
Rahu and Ketu are the personal eclipse points. Therefore, Rahu and Ketu are domains one needs to work on. They control one’s Karma past as well as future. Thus, they are our Karmic responsibilities. We have to learn to look beyond the momentary darkness that Rahu and Ketu represent. They not only highlight but also show negative side of our characters. We require overcoming our interests in worldly achievements and moving towards spiritual growth. They work mentally therefore it is hard to pin- point their result. Rahu and Ketu are the axis of life. They show paths of spiritual growth from the past life [Ketu] to the future [Rahu]. Knowledge of the past and the present are both needed for a better understanding of life. The past shapes the personality we now are. Also, the negative and the positive Karma we are going to experience. It shades our mind to how we are going to tackle the present. Since the future is always uncertain, it can cause fear and uncertainty within it. Future’s uncertainty seems to be in darkness. We have to really come to terms with our past. This would help us from not getting afraid of the future. Rahu shows direction in this life towards the future. On the other hand, Ketu blocks because of our actions of the past.
Rahu and Ketu have twin purposes. One in mundane life and another in spiritual life; both are tangled like their shadowy nature. Their actions in material area exist so that we change our ideas of our desires. What is darkness to a person trapped in materialistic ambitions? It can be powerful spiritual energy for those on path of Moksha or spiritual enlightenment.
Nodes always serve opposing purposes namely good and bad, plenty and nothing, give and take. While Rahu gives, Ketu takes away. There are no straight rules about them. They operate in many different colours. They can lead you to the highest spiritual summit. Also, they can grant you the greatest financial achievements or even great loss. They can give contrary results. You can never predict with precision and surety.
Rahu and Ketu can create fear of unknown. They can create sudden and unexpected results. There is a saying that Rahu and Ketu always take away what they give. This is because Rahu and Ketu have special reason for granting you your wishes. Rahu and Ketu give what you want. However, after achieving it, they make you understand that you are not interested in it. Both Rahhu and Ketu highlight this discontent within our self.
Vedic Hymn to Rahu:
'Rahu is snake shaped, born of a lioness and a devourer of the Sun and the Moon'
Rahu is the head part of the celestial snake. This hymn refers to Rahu being snake shaped. The snakes are given great importance in Vedic mythology. Lord Shiva has a snake around his neck and Lord Vishnu's throne was Shesh Naga, the eternal serpent. Shesh Naga represents the cycles of time and space which the seed of cosmic creation. The Nagas are shaped like snakes but they stand tall. These Nagas are highly evolved beings. They are wise but their wisdom can be used for both good and bad deeds. The Naga sheds his skin, this symbolises transformation and re-birth. The snakes in Vedic literature remind people of their mortality.
The 'devouring of the Sun and Moon' are when Rahu eclipses the leading lights. This illustrates important role Rahu plays in changing the course of our lives. Sun and Moon are royal planets. Under their command the universe and life on earth revolves. However, Rahu can darken this light and can control the process of life. Sun is the Soul and Moon is the mind. When they are eclipsed, they go through renewal, transformation and death.
Rahu leads people away from past Dharmic path. In addition, Rahu tempts them to destroy self. There is a very definite reason why Rahu does this. Rahu wants you to learn, taste and feel everything to one’s complete satisfaction of senses. One would turn into a new leaf with self realisation and find their true enlightenment. Rahu on a physical plane gives one insatiable desire to achieve, to conquer. Once you have reached the highest achievement. You realise this success has not brought happiness with it. Thus, you were chasing an illusion. In India, many cults preach how to satisfy all mundane and carnal desires. One can learn important lessons of fulfilment of desires; however, these do not bring true happiness.
Rahu signifies foreigners in all fields- people, countries and tastes. Rahu behaves like Saturn. Rahu deals with drugs, poisons, over ambition, power play and hidden knowledge. Rahu's element is air. Rahu deals with all features of air, air travel, air accidents, aviation, pilots etc. Other important traits of Rahu include influence on Astrology students, metaphysical knowledge and witchcraft. Also, Rahu is responsible for skin diseases and small pox and other diseases. Rahu causes deception, politics, political plot, inventions, scientists, execution, disappointment etc.
Rahu and the Nakshatras:
Rahu and Ketu rule 3 Nakshtras [fixed stars] each. Rahu rules Ardra [6 degrees 40' to 20 degrees 00' Gemini]. Rahu rules Swati [6 degrees 40' to 20 degrees 00' Libra]. Rahu rules Shatabishak [6 degrees 40' to 20 degrees 00' Aquarius]. These are all in the air as a group of three. Mercury, Venus and Saturn represent thinker, pleasure and honourable behaviour. Rahu has the capacity to grant in all these areas.
Being ruler of fixed star Ardra [6 degree 40' to 20 degrees 00' Gemini], Rahu symbolises highest thinking. Ardra is Nakshatra where we begin our learning about the nature's law. Ardra is in 6 degree 40' to 20 degrees Gemini a sign ruled by Mercury. At cosmic stage of Ardra, there is clash on the outer level. This is where we are unhappy with our present surrounding. Hence, we start looking for answers. This can be through knowledge, occult and communication. The duality of Gemini as well as the celestial powers of Mercury is present. Ardra's symbol is the head or a single jewel. Both of these symbolises ideas, mind and thinking. Rahu is always about high ambition. Thus, in Ardra Rahu combines ambition with the capacity for knowledge. Planets in Ardra get inspired towards greater occult learning. Rudra, a form of Shiva and God of Destruction, is Ardra's presiding deity. Rudra's aim is to destroy ignorance. Hence, he directs consciousness towards knowledge. Also, finding answers for ourselves about this expression. At Ardra we start to study or learn about the Law of Nature. The first time we become discontent with materialistic character of our lives. Also, commence towards expanding horizons of our spiritual selves.
The Second Nakshatra ruled by Rahu is Swati [6 degrees 40' to 20 degrees 00' Libra]. Planets in Swati indicate the depth of the soul's involvement in materialism. The indicator of the soul is in the chart. The Sun is harmed here and Saturn, the worker of the Zodiac, is high-ranking. Under Swati, there is an urge for material gain. Venus rules the earthly needs in an individual. Combining Swati with Rahu, there is more desire for success, wealth and finance. Many millionaires are born with their Moon or Saturn in Swati. The presiding deity is Vayu [air] and the symbol is Coral. The location of this Nakshatra is in Libra. This shows experience of full involvement of earthly, materialistic pleasures. These would bring discontent because scales would be heavy on one side. Once success is achieved one feels empty, lonesome, and dissatisfied with achievement. Many try for more success. However, at this time, best thing would be to look towards one’s higher self. As a Libra, one starts to think about spiritual meaning of life. However, this occurs only after other urges have been fulfilled.
Shatabishak [6 degrees 40' to 20 degrees 00' Aquarius] is the final Nakshatra ruled by Rahu. Aquarius is ruled by Saturn. Rahu's leadership of the Nakshtra makes a very difficult combination. When there is life with definite purpose, it is about learning lessons. Rahu gives results like Saturn but on a mental or emotional level. This double Saturn influence on planets placed here is difficult to handle. However, when the activities are directed towards service to humanity, there is a lot of relief. Here, both Rahu and Saturn are concerned about changing our purpose of life. They give us the final answers. Rahu controls the internal level while Saturn manages external level offers restrictions, obstructions and transformation. One should understand the need to understand final lessons of life and duties to others. These are two of the important aspects of Shatabishak. The symbol of Shatabishak is a flower with thousand petals. Shatabishak is present with Kundalini flowers where we reach towards full awareness of consciousness. This is the stage in life where we activate the Sahasara [Crown] Chakra. Rahu brings forth its full power as the teacher of cosmic law. When the Moon is in Shatabishak, its materialistic tendencies are shed completely. Also, we move towards the true purpose of life. We are ready to transcend to the next phase of spiritual development.
All quarters of Rahu's Nakshatra are ruled by Jupiter and Saturn. These have the implication of spirituality and occult initiation. They are Sagittarius, Capricorn, Aquarius and Pisces. Each pada [quarter] represents the ninth harmonic of the birth chart. Together these four signs represent the final stages of spiritual development. Rahu Nakshatras represent a point in cycle of life where we are starting to change. These padas further indicate that life on an internal level remain the same again. Sagittarius influences man to learn how to control base emotions. Also, change from animal to human habit and behaviour. Capricorn influences our learning about duties and responsibilities to others. Aquarius represents the stage of development where we are now benefiting full knowledge. Pisces influences us to make the final change, sow the seeds for future growth. Hence, though the stages of soul's journey are different in Ardra [Gemini], Swati [Libra] and Shatabishak [Aquarius]. The underlying urge represented by quarters is still the same-to evolve. There is ending of one way of life while there is the beginning of another.
Vedic Hymn to Ketu:
'Decked in silk, flowers, garlands, sandal paste and an umbrella, of variegated colour, born of Jaimini's family under Abhijit Nakshatra…'
Ketu is the lower part of the celestial snake.
This hymn shows the main difference between Rahu and Ketu. Rahu is dark in colour while Ketu has a variegated colour. Therefore, Ketu is capable of shining the light on you suddenly, bringing bout enlightenment.
Ketu is born to the Jaimini family who followed the Mimasa School of philosophy. Their main concern was the correct interpretations of the Vedic rituals. Also, the other interest was settling any controversies about the Vedic texts. Ketu guides towards meditation of nature of creation, perceptive and true understanding of universe. Ketu guides the soul towards knowing oneself and to final salvation or Moksha.
Ketu causes great obstruction in your paths. It sets up roadblocks, traffic jams, boulders in your journey of life. It causes pain too. It wants to change your mind. You learn to leave your excess aggage of past Karma behind. You want to travel lightly into your this existence. You would understand that there are different areas of your life. Some of them you have to address while some have to be left behind. Those who are cannot harness powers of Ketu, understand karmic path lead a sorrowful existence. Sometimes it is difficult for anyone to stand in the way of Ketu power. We need to accept and understand the divine plan. This is part of our destiny. Ketu is doing its work to produce in you the enlightenment. This would lead to true enlightenment and honour. The effect of Ketu problems are going through ritual of fire. One comes out stronger, more powerful, and able to take more problems thrown at us.
Ketu would act like Mars and so would its saver. Fiery in nature, it signifies accidents or injury especially due to fire.
Ketu rules 7 years in the planetary life cycle. Ketu always has a sting in its tale. So the ending of Ketu Maha Dasha one has to be vary of unexpected happening
Ketu is considered the keeper of the book of our life- past and present Karmas.
Ketu is known as Dhwajah flag. Its association with shame with a planet has the capacity to boost its capabilities. There are good or bad beyond recognition for lotteries and windfall. Ketu in conjunction with a benefit can give beyond your wildest expectations.
Some important characteristics of Ketu include ascetics, assassinations, trouble through cats, mind reader, and thought. Also, others are desire for knowledge, deep thinking, imprisonment, poison, plotting, magical powers, poverty, mysticism etc.
Ketu and the Nakshatras:
The Nakshatra's Ketu rules are Ashwini [Aries], Magha [Leo] and Mula [Sagittarius], the fire triple. These are the beginning stages in the cycles of life. Mars, Sun and Jupiter- rulers of Aries, Leo and Sagittarius are friendly with each other. Together, they represent strength, soul and wisdom. Ketu has the capacity to bestow in these areas too. Proper blend of these three planets in our birth charts guide us towards seeking Moksha. The final liberation from cycle of life and death is known as Mokhsha.
Aries deals with birth, new life, freshness of approach and start of cycle of Life.
0 degrees to 13 degrees 20 is Ashwini, the first Nakshatra ruled by Ketu. Ashwini indicates the beginning of the soul's journey into the earthly life. Ketu's rulership of this part of Zodiac is full of occult significations. Ketu is the representative of Moksha. Beginning part of life shown by Aries and ruled by Ketu Nakshatra. This shows true reason of our manifestation on earth is to find the Moksha. This is the final salvation from cycles of life and death. In this stage, the mind should be very pure. We have not yet entangled ourselves into knots that represent attachment to life. Sun, the noteworthy of the soul and our inner consciousness is high in Ashwini. Ashwini is in Aries ruled by Mars. Ketu acts like Mars but on a mental level so the purity of extraterrestrial action. Courage and protection of humanity is powerfully indicated by the planets located here. The past life connection is very strong as Ketu, especially if the Moon is located here.
Magha is second Nakshatra ruled by Ketu. Magha is in sign of Leo [0 degrees to 13 degrees 20' Leo] ruled by Sun. Magha is the beginning of second cycle in soul's Journey. Signs Leo to Scorpio indicates soul's full involvement into pleasures and pains of earthly life. Ketu, important of spiritual realisation rules the starting point of materialistic journey. It shows importance of experience of realities of life in fulfilling divine mission of soul. Magha's ruling deity is Pitris, who are fathers of humanity. These fathers have only one mission. The children are guided to remain on the right path. Fathers interfere when children go off the path. Ketu and Pitris both guide the soul towards its special mission in life. Planets in Magha are idealistic even if their mission is to fulfil their materialistic needs. This does create misunderstandings at times. Others suspect their honour and sincerity. Magha gives away a lot of materialistic wealth. However, person ruled by Magha knows intuitively that material happiness is only an experience. The person still needs to follow the inner purpose of life and move towards Moksha.
Mula is the third Nakshatra ruled by Ketu. Mula is 0 degrees to 13 degrees 20' Sagittarius. It is the beginning of final part of soul's mission. This is towards finding answers. Those would lead to his breaking away from cycles of life and death. Malu is one of the most difficult Nakshatra for planets situated in specially the Moon. The deity that rules Mula is Nittriti, the Goddess of death and destruction. This typifies damage of material sheaths and foundation on which spiritual enfoldment can be undertaken. The pain experienced by the influence of Mula changes the personality. The attachment to worldly pleasures has to be cut off for new spiritual beginning happen. This is the Nakshatra of initiation towards spiritual realisation. Ketu fulfills its role as Moksha Karaka by arousing soul towards its ultimate destination. Mula means root. It is Muladhara chakra [Base Chakra] where the Kundalini power lies dormant. It has to be activated. Ketu rules this. Rahu with leadership of Shatabishak, Crown Chakra, shows real spiritual insight provided by nodes. At times they create powerful negativity to focus your mind towards the absolute knowledge.
The quarters of Ketu's Nakshatras are ruled by Mars, Venus, Gemini and the Moon. Mars is courage, Venus- guide to material fulfilment, Mercury - pure intellect and Moon - emotional Mind. The signs of planets namely Aries, Taurus, Gemini and Cancer- lead soul towards experiencing life on earth. Each pada [quarter] represents the ninth harmonic of the birth chart. Together these four signs represent the beginning stages of spiritual development. Ketu Nakshatras represent point in lifecycle. This is when we have to move towards divine mission of the soul. They always show beginning and an ending at two different levels. Aries is about discovery of new ideas and the courage to explore them. Taurus is where we nurture the creative potential of our new beginnings. Gemini develops the mind and recognition of time, space, the working of the universal law. Cancer makes time and space possible. It is ruled by the Moon and Water which also leads us. This is done towards purification of mind and fitting spiritual and material. The stages of soul's journey are different in Ashwini [Mars] Magha [Leo] and Mula [Sagittarius]. The underlying urge represented by the quarters is still the same- to evolve. Thus, the ending of one way of life is always the beginning of another.
Kaal Sarpa Yog:
Kaal Sarpa Yog is formed when Rahu Ketu hem in the planets in the birth chart. Rahu is 10 degrees Leo, Ketu 10 degrees Aquarius and all planets within these degrees. Either from Leo to Aquarius or Aquarius to Leo [Vedic Astrology does not use the outer planets Uranus, Neptune and Pluto]. This Kaal Sarp Yog is formed when no planet reunites with Rahu or Ketu. It restricts completely any indications of the charts. However, capable the person his life is impeded due to past Karma. Important lessons have to be faced in this life. When there is no amount of effort is rewarded. There are hurdles encountered at every junction for mysterious reasons.
The Yog does not suggest either success or failure. Person caught up in Karmic forces have restricted destiny. It acts mysteriously, without other indications in the birth Chart. A heavy price is paid for past Karma in this life. One has to understand and by counter-acting affects of Kaala Sarpa Yog. One needs to move towards higher self. As Rahu and Ketu act on the inner self. There is need to understand significance of mental implication and inner blocks created by this combination.
Transits of Rahu and Ketu can be analysed by looking at other planets they combine with. The Sun and Moon are the most important planets. In 1998 Rahu and Ketu were transiting through Leo Aquarius Axis. People with Leo Sun, Moon, Ascendant and Aquarius Sun, Moon, Ascendant felt transforming effects of Rahu Ketu. Transit of Rahu Ketu gives hints to their unpredictability. They normal travel in a retrograde motion, the opposite to other planets. They would suddenly go direct and backwards again, representing the churning process. They can churn up your life. They work on inner emotion, forces one to transform oneself, create unpredictability in your life. One has to study eclipses to know the precise powerful influences of them. Eclipses might take place within 1 to 2 degrees of your birth planets. This would indicate a time for change. Here it is important to remember that the eclipses work on mental level. Some of the influences might not be immediately obvious but would reveal themselves in time.
The transit of Rahu also needs to be seen through their Dashas- planetary cycles. They are each assigned a Mahadasha. Rahu has an 18 year period and Ketu a 7 years period. They have sub- periods in planetary cycles of other planets. Through these they exercise their power and influence. Life cycles come into our life and they have overall control over factors. Hence, they dictate what we would be are going to be doing.